JPH11312751A - Package for high-frequency circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package for high-frequency circuit, which is low in the reflection losses in the input/output part of a high-frequency signal, can also be shielded from electromagnetic waves and has low-loss transmission characteristics for the high-frequency signal. SOLUTION: This package is for the high-frequency circuit of a structure, wherein the package is provided with an insulating board 21, having a lower ground conductor layer 26 and a mounting part 21a for a high-frequency circuit component 28, a line conductor 24 and the same surface ground conductor layers 25, which are provided from the vicinity of the mounting part 21a, extending over the vicinity of the outer periphery of the mounting part 21a, and an insulating frame body 22, which is bonded on the board 21 and is formed with an upper ground conductor layer 27, and with castellation conductors 32, which connect the layers 25 with the layer 27, formed on the inner and outer side surfaces of the frame body 22, through conductors, which connect the layers 25 with the layer 26 are respectively formed in the parts, which are located directly under the conductors 32 of the insulating board 21. The ground state of the package is stable, and the reflection loss and radiation loss of the package can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency circuit package for accommodating high-frequency circuit components such as high-frequency semiconductor elements and high-frequency circuits used in a high-frequency band.

[0002]

2. Description of the Related Art A high-frequency circuit package used for accommodating high-frequency circuit components such as a high-frequency semiconductor element or a high-frequency circuit operating in a high-frequency band of a MHz band or a GHz band is conventionally shown in, for example, FIG. And FIG. 6 shows a plan view of the main part.

In FIGS. 5 and 6, reference numeral 1 denotes an insulating substrate having a mounting portion 1a made of ceramic or the like and having an upper surface on which a high-frequency semiconductor element is mounted and accommodated, and 2 denotes a mounting portion 1a made of ceramic or the like on an insulating substrate 1. The insulating frame 3, which is joined so as to surround and serves as a side wall of the housing, is a lid for hermetically sealing the housing. The insulating substrate 1, the insulating frame 2, and the lid 3 form a semiconductor for high frequency. An accommodating portion 9 for accommodating the element is formed.

Reference numeral 4 denotes a line conductor for transmitting a high-frequency signal disposed so as to conduct inside and outside of the housing 9 from the vicinity of the mounting portion 1a to the vicinity of the outer periphery of the insulating substrate 1; The line conductor 4 and a part of the same-surface ground conductor layers 5 and 5 are sandwiched between the insulating substrate 1 and the insulating frame 2 to form a hermetically sealed portion. I have. Reference numeral 6 denotes a lower ground conductor layer formed on the lower surface of the insulating substrate 1, and reference numeral 7 denotes an upper ground conductor layer formed on the upper surface of the insulating frame 2. Reference numeral 8 denotes a high-frequency semiconductor device mounted on the mounting portion 1a and housed in the housing portion 9, and its electrode 10 and the line conductor 4 and the portions of the same-surface ground conductor layers 5.5 exposed in the housing portion 9 are formed. They are electrically connected via bonding wires 11.

In such a conventional package for a high-frequency circuit, the configuration of the input / output portion of the high-frequency signal includes a line conductor 4 for transmitting the high-frequency signal and an insulating substrate 1 with the line conductor 4 interposed therebetween.
Ground conductor layers 5.5 provided on both sides on the same plane
And a lower grounding conductor layer 6 on the lower surface of the insulating substrate 1 and an insulating frame 2
A coplanar line with upper and lower grounds is provided at a portion (airtightly sealed portion) where the line conductor 4 and the same-surface ground conductor layer 5.5 are sandwiched between the insulating frame 2 and the insulating substrate 1. A coplanar line structure with a lower ground is formed on both sides of the insulating frame 2.

In such a high frequency signal input / output section, the electrical connection between the same plane ground conductor layers 5 and the ground is located below the insulating frame 2 as shown in FIG. Through conductors 12 such as via conductors formed in insulating substrate 1
This is performed by electrically connecting the lower ground conductor layer 6 with the lower ground conductor layer 6.

[0007]

In such a conventional high-frequency circuit package, the characteristic impedance of the line conductor 4 depends on the dielectric constant of the insulating frame 2 existing above the line conductor 4 in the hermetically sealed portion. However, there is a problem that characteristic impedance mismatching occurs between them, so that reflection loss of a high-frequency signal increases and transmission characteristics of a high-frequency signal deteriorate.

For this reason, there has been proposed a technique for matching the characteristic impedance between the hermetic sealing portion and the portions on both sides thereof. For example, Japanese Patent Publication No. 8-12887 discloses a balanced strip line structure (a coplanar line structure with upper and lower grounds). A method has been proposed in which the width of the wiring in the hermetically sealed wiring portion is narrower than the width of the wiring in the internal wiring portion that forms another microstrip line structure (coplanar line structure with lower ground).

According to this, since the width of the hermetically sealed wiring portion is made smaller than the width of the internal wiring portion, the characteristic impedance of the internal wiring portion and the characteristic impedance of the hermetically sealed wiring portion can be matched. There is an advantage that the impedance can be matched with the characteristic impedance of the terminal, and the propagation characteristic of a high-speed signal can be improved.

However, even when the characteristic impedance of the wiring of the hermetically sealed wiring portion and the wiring of the internal wiring portion corresponding to the portions on both sides thereof are matched by such a method, the line conductor moves to the hermetically sealed portion. Portion (portion immediately below the side wall of the insulating frame 2 indicated by A and B in FIG. 6)
In this case, since the upper ground conductor layer 7, the same plane ground layer 5, and the lower ground conductor layer 6 are not directly connected to each other, the ground state tends to be unstable, and the characteristic impedance locally changes at this portion. Will cause reflection loss,
In addition, since the shielding effect of the high-frequency signal is insufficient at this portion and radiation loss occurs, there is a problem that the transmission characteristics of the high-frequency signal are deteriorated by these losses.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the reflection loss at the input / output portion of a high-frequency signal, to enable electromagnetic shielding, and to reduce the loss to a high-frequency signal. An object of the present invention is to provide a high-frequency circuit package having excellent transmission characteristics.

[0012]

According to the present invention, there is provided a high-frequency circuit package comprising: an insulating substrate having a lower grounding conductor layer formed on a lower surface and a mounting portion on which a high-frequency circuit component is mounted on an upper surface; A line conductor disposed from the vicinity of the mounting portion to the vicinity of the outer periphery, a coplanar ground conductor layer provided on both sides of the line conductor, the line conductor and the coplanar ground conductor surrounding the mounting portion on the insulating substrate; An insulating frame having an upper grounding conductor layer formed on an upper surface thereof, wherein the same plane grounding conductor layer and the upper grounding conductor layer are formed on inner and outer surfaces of the insulating frame. Forming a castellation conductor to be connected, and forming a through conductor for connecting the same-plane ground conductor layer and the lower ground conductor layer to the insulating substrate immediately below the castellation conductor, respectively. It is characterized in.

According to the high-frequency circuit package of the present invention, a lower portion of the line conductor for transmitting the high-frequency signal is provided in the hermetically sealed portion sandwiched between the insulating substrate and the insulating frame via the insulating substrate. The grounding conductor layer is provided with an upper grounding conductor layer via an insulating frame, and a coplanar grounding conductor layer is provided on both sides of the grounding conductor layer. Since the castellation conductors connecting the conductor layers were formed, and the through conductors connecting the same-plane ground conductor layer and the lower ground conductor layer were formed on the insulating substrate immediately below the castellation conductors, the line conductor was insulated. The line configuration of a portion of the inner and outer surfaces of the frame that enters and exits the hermetic sealing portion has a pseudo waveguide structure. As a result, it is possible to stabilize the grounding state of the conductor for grounding surrounding the line conductor to reduce the reflection loss, and to enhance the electromagnetic wave shielding effect to suppress the radiation loss. The transmission characteristics of the high-frequency signal at the input / output unit can be improved with low loss.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing an example of an embodiment of a high-frequency circuit package according to the present invention, and FIG. 2 is a plan view of a main part thereof. FIG. 3 is a cross-sectional view taken along line CC ′ of FIG. 2, and FIG. 4 is a cross-sectional view taken along line DD ′ of FIG.

In these figures, reference numeral 21 denotes an insulating substrate having a mounting portion 21a on the upper surface of which a high-frequency circuit component is mounted, and 22 denotes an insulating substrate 21 which is bonded to surround the mounting portion 21a and accommodates the high-frequency circuit component inside. It is an insulating frame which becomes a side wall of the accommodating part. An accommodating portion 29 for accommodating the high-frequency semiconductor element is formed by the insulating substrate 21 and the insulating frame 22, the high-frequency circuit component 28 is mounted on the mounting portion 21a, and the lid 23 is closed so as to cover the accommodating portion 29. Is bonded to the upper surface of the insulating frame body 22, so that the high-frequency circuit component 28 is hermetically sealed and housed inside the housing portion 29.

Reference numeral 24 denotes a line conductor for transmitting a high-frequency signal disposed so as to conduct inside and outside the housing portion 29 from the vicinity of the mounting portion 21a to the vicinity of the outer periphery of the insulating substrate 21. The line conductor 24 and a part of the same-plane ground conductor layers 25 and 25 are sandwiched between the insulating substrate 21 and the insulating frame 22 to form a hermetic sealing portion. I have. 26 is a lower ground conductor layer formed on the lower surface of the insulating substrate 21, and 27 is an upper ground conductor layer formed on the upper surface of the insulating frame 22. Reference numeral 28 denotes a high-frequency circuit component such as a high-frequency semiconductor element or a high-frequency circuit mounted on the mounting portion 21a and housed in the housing portion 29. The electrode 30 and the line conductor 24 and the housing portion of the same-surface ground conductor layer 25 The portion exposed in 29 is electrically connected via bonding wire 31.

Reference numeral 32 denotes a castellation conductor for electrically connecting the upper ground conductor layer 27 on the upper surface of the insulating frame 22 and the same ground conductor layers 25, 25 on the inner and outer surfaces of the insulating frame 22,
For example, it is formed by applying a conductor layer to the surface of a concave portion provided on the inner and outer surfaces of the insulating frame 22. Reference numeral 33 denotes through conductors such as through-hole conductors and via conductors that electrically connect the same-plane ground conductor layers 25 and 25 and the lower ground conductor layer 26 on the lower surface of the insulating substrate 21 directly below the castellation conductor 32, respectively. .

In such a high-frequency circuit package of the present invention, the insulating substrate 21 and the insulating frame 22 are
In the hermetically sealed portion formed by joining a part of the grounded conductor layers 25 and 25 on the same plane, the upper grounded conductor layer 27 and the castellation conductor The ground conductors 25 and 25, the through conductors 33 and 33, and the lower ground conductor layer 26, which are on the same plane as 32 and 32, form a continuous conductor in a ground state so as to surround the line conductor 24 that transmits a high-frequency signal. Therefore, the line configuration of this portion becomes the configuration of the pseudo waveguide line. As a result, it is possible to stabilize the grounding state of the conductor for grounding surrounding the line conductor 24 and reduce the reflection loss of the high-frequency signal in the hermetic sealing part, and to suppress the radiation loss by enhancing the electromagnetic wave shielding effect. And the generation of higher-order modes can be suppressed.

As a result, the reflection loss and radiation loss of the high-frequency signal in the input / output section of the high-frequency signal are suppressed, and the deterioration of the transmission characteristics is suppressed, so that a high-frequency circuit package having low loss and good transmission characteristics is obtained.

In the high-frequency circuit package of the present invention, the insulating substrate 21 and the insulating frame 22 are made of, for example, a ceramic material such as alumina or mullite, an inorganic material such as glass ceramic, or Teflon (PTFE).
Resin-based materials such as glass epoxy and polyimide are used. The shapes and dimensions (thickness, width, and length) of the insulating substrate 21 and the insulating frame 22 are appropriately set according to the frequency and characteristic impedance of the high-frequency signal used.

The insulating frame 22 and the insulating substrate 21 may be usually made of the same material, but different materials are used to make the dielectric constant of the insulating frame 22 different from that of the insulating substrate 21. Is also good. In this case, for example, the insulating frame body is
The dielectric constant of the insulating frame 22 is preferably low, and the dielectric constant of the insulating frame 22 is preferably as close as possible to the vacuum dielectric constant. This is preferable in that the change in the propagation mode of the high-frequency signal at the junction between the insulating substrate 21 and the insulating frame 22 and the other portions is reduced, and the transmission loss is reduced.

The line conductor 24 is a metal material for a high-frequency line conductor, for example, Cu, MoMn + Ni + Au, W + Ni + A
u, Cr + Cu, Cr + Cu + Ni + Au, Ta ₂ N +
NiCr + Au, Ti + Pd + Au, NiCr + Pd +
It is formed by a thick film printing method or various thin film forming methods or a plating method using Au or the like, and its thickness and width are appropriately set according to the frequency and characteristic impedance of the transmitted high-frequency signal. The line width of the line conductor 24 at the joint between the insulating frame 22 and the insulating substrate 21 may be narrower than the line width at other portions. Is set as appropriate according to the required specifications from the width corresponding to the line width to the line width in other portions.

The same plane ground conductor layer 25 may be formed of the same material as the line conductor 24 by the same method, and the distance between the line conductor 24 and the same plane ground conductor layer 25 is the same as that of a common plane ground conductor. The standard setting when providing a layer may be used. Further, at the joint between the insulating frame 22 and the insulating substrate 21, the same-surface ground conductor layer 25 may be protruded at equal intervals toward the line conductor 24, so that the characteristic impedance may be more precisely matched. In such a case, an appropriate setting may be made according to the required characteristics in consideration of the degree of electromagnetic field influence.

Lower ground conductor layer 26 and upper ground conductor layer 27
May be formed using the same material as the line conductor 24 and the same-surface ground conductor layer 25 by the same method. These may be formed by attaching another conductive member, for example, a metal plate or a metal block, in addition to the case where they are formed as a conductor coating layer.

The castellation conductor 32 is provided in a recess or the like formed on each of the inner and outer surfaces of the insulating frame 22 directly above the same-plane ground conductor layer 25 and is flush with the upper ground conductor layer 27.
25 and is formed so as to be electrically connected to each other, and may be formed by applying the same method using the same material as each of the above-described conductor layers, and other conductive members, for example, a metal plate or a metal block. It may be formed by attaching.

Further, the through conductors 33 are provided on the insulating substrate 21 immediately below the castellation conductors 32 in the same plane ground conductor layer.
25 and the lower ground conductor layer 26 are formed so as to be electrically connected, for example, by forming a through-hole conductor or a via conductor, or by embedding a metal plate, a metal rod, or a metal pipe. Good.

In manufacturing the high-frequency circuit package of the present invention, if the insulating substrate 21 and the insulating frame 22 are made of glass ceramic, for example,
Prepare a green sheet of glass ceramics that will be
After a predetermined punching process is performed on this to form a through-hole serving as a through-conductor, a low-resistance conductive paste such as copper or silver is filled into the through-hole by a screen printing method, and a predetermined line conductor pattern and a conductor layer are formed. Print and apply to the pattern shape. Next, a separately prepared glass-ceramic green sheet is punched out in a frame shape so that a concave portion for forming the castellation conductor 32 is formed on a side surface thereof, and a high-frequency semiconductor element 28 is formed on the upper surface of the green sheet serving as the insulating substrate 21. Are laminated and adhered so that the accommodating section 29 is formed, and finally, they are integrally fired at about 1000 ° C.

If the gap g between the castellation conductors 32 is set to a value smaller than the gap g ₀ expressed by the following equation, attenuation of high-frequency signals due to resonance can be avoided. At the frequency of the high-frequency signal to be transmitted, its transmission characteristics can be improved. g ₀ = C ₀ / 2f · √ε _reff where g ₀ is a castellation conductor where resonance occurs.
32 gap, _C0 is the speed of light, f is the frequency of the high-frequency signal,
ε _reff is a relative dielectric constant obtained by combining the relative dielectric constants of the insulating frame 22 and the insulating substrate 21.

When the castellation conductor 32 is formed in a concave portion on the side of the insulating frame 22 as in the high-frequency circuit package shown in FIGS.
As the depth increases toward the center of 22, the pseudo-waveguide structure extends over a longer distance, so that the grounding state becomes more stable and the transmission characteristics of high-frequency signals can be further improved. Therefore, the concave portion on the side surface of the insulating frame body 22 where the castellation conductor 32 is formed
It is desirable to form as deep as possible as long as the hermetic seal inside can be maintained.

Using such a high-frequency circuit package, a high-frequency circuit component 28 is mounted on the mounting portion 21a, and its electrode 30 is connected to a line conductor located in the housing portion 29 via a bonding wire 31, a bonding ribbon, or the like. 24 and the ground conductor layer 25 on the same plane.
A lid 23 made of an Fe-Ni alloy such as e-Ni-Co or Fe-Ni42 alloy, oxygen-free copper, aluminum, stainless steel, Cu-W alloy, Cu-Mo alloy, etc.
By attaching with a low melting point metal brazing material such as Sn brazing, a high melting point metal brazing material such as AuGe brazing, or seam welding (welding), the high frequency circuit component 28 is hermetically sealed and housed inside the package. It becomes a high-frequency circuit device as a product.

Then, this is mounted on an external electric circuit board, and the line conductor 24 and the same plane ground conductor layer 25 located outside the insulating frame 22 are bonded to the wiring conductor of the external electric circuit by bonding wires or ribbon lead terminals. By electrically connecting the high-frequency circuit component 28 inside the package and an external electric circuit by using the above-mentioned components, the device is used as a high-frequency circuit device.

It should be noted that the present invention is not limited to the above-described embodiments, and that various changes and improvements can be made without departing from the scope of the present invention. For example, a plurality of line conductors 24 and the same plane ground conductor layer 25 may be provided as necessary as an input / output unit for a high-frequency signal.
Further, the structure of the input / output unit may be applied, for example, as the structure of the input / output unit of a so-called metal wall type package in which the housing is surrounded by a metal wall.

[0034]

According to the high frequency circuit package of the present invention, the lower grounding conductor layer is provided in the hermetically sealed portion between the insulating substrate and the insulating frame with respect to the line conductor for transmitting the high frequency signal. And an upper grounding conductor layer, a grounding conductor layer on the same plane is provided, and a castellation conductor connecting the grounding conductor layer on the same plane and the upper grounding conductor layer is formed on the inner and outer surfaces of the insulating frame. Since the through conductors that connect the same plane ground conductor layer and the lower ground conductor layer are formed on the insulating substrate, the line configuration of the part where the line conductor enters and exits the hermetically sealed portion on the inner and outer surfaces of the insulating frame is simulated. As a result, it has a waveguide structure, and as a result, it is possible to reduce the reflection loss by stabilizing the grounding state of the grounding conductor surrounding the line conductor, and to suppress the radiation loss by enhancing the electromagnetic wave shielding effect. Rukoto can, thereby, can be made excellent in low loss transmission characteristics of the high-frequency signal in the input-output section of the high-frequency signal.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of an embodiment of a high-frequency circuit package according to the present invention.

FIG. 2 is a plan view of a main part of the high-frequency circuit package shown in FIG. 1;

FIG. 3 is a sectional view taken along line C-C ′ of FIG. 2;

FIG. 4 is a sectional view taken along line D-D 'of FIG.

FIG. 5 is an exploded perspective view showing an example of a conventional high-frequency circuit package.

FIG. 6 is a plan view of a main part of the conventional high-frequency circuit package shown in FIG.

[Explanation of symbols]

 21 ... Insulating substrate 21a ... Mounting section 22 ... Insulating frame 23 ... Line conductor 25 ... Coaxial ground conductor layer 26 ... Bottom Ground conductor layer 27 Upper ground conductor layer 28 High-frequency circuit components 32 Castellation conductor 33 Through conductor

Claims (1)

[Claims] An insulating substrate having a lower ground conductor layer formed on a lower surface and a mounting portion on which an RF circuit component is mounted on an upper surface, and a line conductor disposed from the vicinity of the mounting portion to the vicinity of the outer periphery of the insulating substrate. And a ground conductor layer provided on both sides of the line conductor, which surrounds the mounting portion on the insulating substrate, and is joined with a part of the line conductor and the ground conductor layer on the same surface sandwiched therebetween. An insulating frame on which a ground conductor layer is formed, wherein a castellation conductor for connecting the same-plane ground conductor layer and the upper ground conductor layer is formed on the inner and outer surfaces of the insulating frame, and the castellation is formed. A package for a high-frequency circuit, wherein a through conductor for connecting the same-plane ground conductor layer and the lower ground conductor layer is formed on the insulating substrate immediately below the conductor.